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Thread: 1972 MGB Project Blue First attempt and fixing no spark and other checks

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    1972 MGB Project Blue First attempt and fixing no spark and other checks

    December 2, 2019

    Today I had the first attempt at getting some work done on Project Blue, my 1972 MGB Project.

    To start, I picked up a used white hood from a 78 model and fitted it to the car. It fits and pretty good. I'll need to screw in the chrome strip, but its on and even though it needs some adjustment its fitting well.

    I got some spark plug testers, and connected them to the plugs. I unplugged the fuel pump just to be safe.

    I then turned the key to the on position with the battery connected and checked and I found I was getting 12v at both coil leads. Weird. I figured one side should be ground.

    I tested ohms at the coil and found a bit over 3 ohms around 3.3 to 3.5. I have 2 coils, and both tested the same on my multimeter. I tested to the center post and found on 20k setting around 6. something so not sure what that means, but still no spark.

    I pulled the distributor, a Lucas 25D and inspected the points they looked a bit funky, so I swapped them with a new set that was in a brand new box that came with the car. I checked and both the condenser wire and the distributor wire were mounted against the spring within the plastic washer insulating them from the post. I adjusted the points and they seem to open and close fine as the distributor rotates.

    I swapped the new looking condenser with another new one that also came with the car. Still no spark.

    Looking at the car's wiring, at the dash there is a red and white wire that is cut, there an aftermarket red wire that is running off the red/white from the switch and running to the starter going into the engine compartment that seems to be bypassing the starter relay. disconnected the red wire and reconnected the red/white and the starter does not turn. bridged them both together and the starter turns, and the red/white wire at the starter relay under the hood will turn the starter over when attached to the lowest fuse.

    There is a blue wire coming off a white wire on the fuse block off the 3rd fuse that is going under the car to the fuel pump. bypassing the internal harness wire. Thats no big deal. I can work on that later. fuel pump clicks on and is one of those aftermarket square gold colored ones. and boy does it make some clicking, but thats all good for now.

    Back to the spark, still no spark found at all. Looking at the engine compartment, it looks like there is a white plug near the alternator with 3 spade connectors aligned in an L shape that is not plugged into anything. There is a wire from the car that is going from the fuse box to the alternator and there are wires on the alternator.

    Coil has the white with black wire connected to the negative post on the coil and the white wire is connected on the positive post.

    Towards the front of the car, on the harness, there is an area with what appears to be two green wires coming out of the harness that is cut. not sure if this is supposed to be fused or joined together, but thats not a big deal for now. This car will need some wiring fixed.

    Pulled the tach, both white wires are connected at the tach. bypassed the tach, still no spark. Reconnected the tach back together.

    Tried with the other coil, still no spark. I suspect that the coils may either both be bad but unlikely. I suspect moreso that there is some kind of wiring issue.

    My next step is to clean up with wire connections everywhere I can see. I plan to probably just cut them all and replace all the ends with new ends, or get some electronics contact cleaner and some stiff bristle brushes and go to town. I will also replace the fuse box with a newer style ATO fuse box I got because its easier to deal with fuse wise for me plus I figured I may as well update it.

    RUST:

    ITs not as bad as it seems. Yes there is a hole on both rear quarter panels and on the front passenger lower fender at the bottom. but the castle rails are solid with only some surface rust. A Little Eastwood rust enscapulator for the frame rails and should be good to go. All it needs are new rear quarter doglegs to be welded in, and the front right lower fender bottom to the welded in. then the rust is clear. Floors all solid.

    The dash has rust on the frame. it was expected, and its not great. so I figure thats going to have to be replaced at some point.

    Until the next time I get to it, I have already done some testing and I'm not really further ahead from where I was, but I was flying blind just going by what I had been reading a bit. I'll remember to take my no spark checklist with me next time. I suspect that I should clean up the wires and replace any bad connections and put the wiring back to as stock as possible before doing anything else, as the problem may simply be in there.

    Worst case is, I buy a whole new harness from britishwiring or one of the other sites that sells them. I know that will cost about as much as what I paid for the car, and spend a good amount of time installing it, But if thats what it takes to fix it so be it.

    I suspect it just needs all the wire connections cleaned and replace a few bad wires. I've got the diagram so once I figure out what wires need to be replaced as per colors, I'll order some matching wires and solder splice in some new sections as needed to get the wiring back to how it should be from original. The multimeter had some trouble getting a good clean contact without scratching at the connecting points to get to the clean metal. so I am suspicious of dirty connections as being a good part of the problem.

    My plans for the car are as follows and not necessarily in this order.
    1. Get spark back / clean and fix wiring issues
    2. Rebuild SU carbs and reinstall them
    3. Replace fuel tank and rubber lines
    4. Go through braking system and ensure it is safe
    5. Ensure all gauges and Lights are working
    6. Change all fluids and bleed all systems
    7. New tires
    8. Fix rust
    9. Paint
    10.. Interior / rubber seals etc around body
    11. Go for a drive and smile ear to ear.

    I'm happy for a few reasons. 1. The rust is not as bad as it looks. 2. I got a replacement hood. 3. I got a line on a whole top for a good price. 4. I'm going to get this thing back on the road that is for sure.
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    Great Pumpkin NutmegCT's Avatar
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Hey - congratulations on the plan, the progress, and the worthy goal!

    If/when you do the wiring job, be sure you take plenty of photos before you start. Lots of posts of "where does this wire go?" teach a valuable lesson.

    What's the history of the car?

    Tom M.
    Mac & Phyllis Take a Trip: http://nutmegflyer.com/trip-details-daily-updates/
    History: 1976 MGB, 1959 Triumph TR3A, 1960 Mercedes-Benz 190b, 1958 Rambler American.
    Current: 1953 MG TD27318.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Well, Alon, it certainly sounds like you've got your hands full! And you have the priorities right with your list. I think you're on the right track by starting from scratch with the wiring, as it appears someone has really botched it up royally. The wiring diagrams from Advance Auto Wire that I linked in your intro post will be your friend there. The key here is the "Keep It Simple" method.

    Keep us posted!

    Mickey
    "There are three kinds of men. One who learns by readin'. The few who learn by observation. The rest of them have to pee on that electric fence for themselves." Will Rogers
    Mickey Richaud - '73 MGB, '69 MGB GT/V6 (both SOLD! ); Victor TF 1800; '03 Jaguar XK8
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Car was sitting 20 years then previous owner was trying to get it to start and no go. Engine spins but no spark. Looks like someone was trying to fix it but just didn't know how so started bypassing some stuff.

    Wiring is not bad overall but I think it needs some TLC. Replace some wires that were bypassed. Maybe replace starter solenoid relay and of course clean it all up to ensure solid connections.

    Would love some good pictures of the engine wiring connections and what the two green wires towards the front of the car are for.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    The secondary winding of the coil (where the high voltage lead connects) should be grounded to the car body through the clamp. The primary winding (the 2 smaller leads) will have 12V on both sides when the points are open. When the points close, one side of the primary grounds, current flows creating a magnetic field. When the points open, the current stops, the induced magnetic field collapses creating the high voltage spike that triggers the spark. If the points are open or the coil not connected to the distributor, then you will see the 12V on both sides of the primary with respect to ground.

    If you have an inductive timing light you can test the coil by connecting a spark plug right to the coil secondary (bypassing the distributor), and then grounding and lifting the ground on the distributor side of the primary. When you lift the ground, the plug should spark. If you don't have an inductive timing light (or the wiring is so borked you're not sure it will get power) connect a loose spark plug to the coil, place or clamp it somewhere it can be grounded, then ground /lift the distributor side of the primary - you should get a spark when you lift. Don't be holding the spark plug in your hand or be touching any part of the secondary wire when you do, unless you enjoy pain. Make sure you are NOT grounding the battery/ignition side of the primary because that would be a dead short.

    A severely corroded coil clamp could keep the secondary from triggering a spark, or a loose/missing/corroded ground strap from the engine to the car body could also interfere since the spark plugs ground through the cylinder head threads.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Ive been doing some research today and found out some interesting information.

    From what I can see, I need to 100% fix up wiring. the alternator was replaced and rewired bypassing the wires in the harness. the starter was wired direct to the switch bypassing the relay. Fuel pump has also been wired off the fuse block with some new wiring same with alternator.

    I ordered a few small tidbits to take care of the wiring.

    Contact cleaner and more contact cleaner. Feeler gauge, new screws for the points base, new low tension wire to the coil, a box of spade and bullet connectors, a replacement alternator plug to adapt the original wires to the alternator which is no longer the one that matches to the plug in the car. and while I was ordering a few parts, I decided to pick up a new valve cover gasket as I will need one of those regardless and it was only a few dollars.

    I also ordered a new haynes manual as the one I got with the car well it has seen better days, so I figured a nice shiny new one would be worth it.

    I also ordered some wire to at least have to replace some wires if needed.

    My initial plan is to pull wire by wire. clean one, put it back, go to the next. I will have my dremel and wire brush handy and will cut and replace connectors if needed I will do this until I have sorted the wires using the wiring guide.

    I'm not going crazy ordering a ton of parts for this thing, I am just going to methodically go through the wiring and tidy and clean it all up so I can move to the next step.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    "My initial plan is to pull wire by wire. clean one, put it back, go to the next. I will have my dremel and wire brush handy and will cut and replace connectors if needed I will do this until I have sorted the wires using the wiring guide."

    You are a patient man! If you're pulling and replacing individual wires, be careful you're not just following the previous owner's "creative work". Also, plastic wire coverings usually deteriorate over the years, and you'll probably find many of the wires look fine at first, but the plastic will crack when pulled or bent.

    When I had my B, it was a major headache to trace wires; previous owner had replaced bad parts of wires with *different colors* and/or with whatever wire he had handy, including lamp wire - usually in the tough spaces like under the dash.

    gack.



    Mac & Phyllis Take a Trip: http://nutmegflyer.com/trip-details-daily-updates/
    History: 1976 MGB, 1959 Triumph TR3A, 1960 Mercedes-Benz 190b, 1958 Rambler American.
    Current: 1953 MG TD27318.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    And so it begins! Thanks for the update - I look forward to reading of your progress, and I know you're gonna have a blast with it. Just remember: the journey is more valuable than the end result...

    ...at least that's what I've always told myself!


    Mickey
    "There are three kinds of men. One who learns by readin'. The few who learn by observation. The rest of them have to pee on that electric fence for themselves." Will Rogers
    Mickey Richaud - '73 MGB, '69 MGB GT/V6 (both SOLD! ); Victor TF 1800; '03 Jaguar XK8
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Even though the points came from a box and are "new", take some #250 wet-or-dry sandpaper and make sure they're shiny-clean! As Yakko explained, when the points close the coil is triggered to dump high voltage to the center of the distributor cap. If you follow his procedure a step at a time, you should get to the bottom of the discontinuity.

    If you've 12V at the "+" side of the coil, and you trigger it manually by make-and-break on the ground side, with a grounded sparkplug connected to the coil directly, it should produce a spark. If not, bad coil.

    If the coils are Lucas, a thing I've seen more than once: The spade connectors are riveted to the body to connect to the coil's internal wires. Those rivets can loosen and corrosion between them and the spade connectors can be a problem. Found more than one "intermittent running" condition due to this.

    And CRC 2-26 is great for use as a contact cleaner. It can be easily found in Home Depot's electrical section.
    '64 MGB, '67 Lotus Elan S-3 DHC,'69 Lotus Elan +2
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    I suggest narrowing your project into phases. Instead of going all out on the wiring start with one problem at a time. For me that would be getting spark for the engine. Save the alternator for another days work, likewise isolate the lighting issues and accessory glitches, this way you will have milestone events to feel good about and not get discouraged by little or no progress. Former owner of three B's
    Thank goodness the MG is finally gone, replaced by another Corvette

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Are you sure you installed the points correctly? Unless they came already set up, that plastic washer must be centered so as to insulate from the base. Check it again. I've done that at least twice in the 65 years I've been messing with these cars. It will drive you crazy when everything checks out but the points don't spark.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Yes I verified the points are installed properly. gapped properly is another story, so I bought a feeler gauge and have been watching videos on how to set the points and Ive got a good idea of that. I am going to replace the low tension lead that connects to the white with black wire going to the coil as mine is well fairly perished so I figured that cannot hurt.

    I have yet to see if the coils are bad, but they ohm out at 3.5 on both terminals so I assumed that means they are good. one is original lucas 12v and one is a lucas sports coil. Worst case is if I test the coil and they are both bad, I'll get a coil, and a good one, either lucas original from one of the online british parts places or a bosch one as mentioned to me by someone. Definitely will not even attempt to save a few dollars to get some no name or DHK (stands for Direct from Hong Kong)(Made in China) Brand.

    As for wiring, its not that badly buggered, but I just want to resolve the few wires that have been messed with. its not horrible. so Ive got some wire, some connectors, some tape, some solder and heat shrink if needed. I just want to have the wiring be working. once its sorted and I know which colors I will need to make it look all original, I will for sure order from british wiring some lengths of the right stuff.

    But for sure the CRC contact cleaner is coming along with some wd40 brand contact cleaner as it has a nice straw to spray into the connectors. I will also use a wire brush to clean them. thats what I mean by going wire by wire cleaning connections. not replacing whole wire sections. unless the wire has to be replaced.

    I suspect the starter relay was bad so they just bypassed it. so I plan to undo the bypass and swap the relay out to ensure that circuit is back to original. The alternator has obviously been changed and like the starter, they bypassed the oem wires so I will also be restoring those back to stock by changing the plug on the alternator to the style that fits direct with the original wiring.

    I'm learning a ton about the wiring by studying the wiring diagrams, so I am sure that I can get it sorted in that respect.

    Long road ahead, I haven't even tried to look at the SU carbs and what parts I will need to put those back on, but Once I have spark, my next step is the fuel system. tank will be inspected, and if rusty, replaced. I wont even bother with trying to salvage it. Rubber fuel lines will be replaced. well all rubber lines will be replaced overall as I go along.

    Once fuel system is 100%, next step will be brakes. rebuild and replace all parts for the front discs and pads and the rear drums, replace brake lines maybe master cylinder and bleed system.

    After that, clutch. replace any rubber lines, and bleed out the system. if need be replace the clutch slave cylinder and servo.

    After that is all square and I know it will have fuel, and will stop. I will work on the carbs to get the SU's rebuilt and installed. I will also plug the air rail holes on the head, and remove the air pump and related parts for it.

    Then the fun part of firing it up begins. if it fires, moves and stops under its own power, change all fluids, inspect for leaks. then take off the wheels and go get new tires.

    Then I can go through and check function of all lights, gauges and switches, and repair, replace or fix as needed.

    Then I can work on cosmetics. I would start with getting the lower doglegs and front fender bottoms replaced. either I will buy a Mig welder and go to town learning how to, or I go to my bodyshop guy and have him just weld in the panels for me, (Including filling the side markers on both front and rear, as I plan to do a custom touch of much smaller cleaner looking ones) then I can grind, fill, prime, block, sand and prime and prep the car for paint.

    At that stage, I can either take it to the bodyshop and get it sprayed, or to a Maaco like place for a simple paint job. If all they have to do is spray the car, I do not see it costing a fortune, b ut if it will and I can rent or buy a portable inflatable paintbooth and tankless sprayer system Then I may just paint it myself. I plan on a lovely Navy Blue color. I think with the autumn leaf interior color it will look gorgeous.

    Once painted. all the rubber trim can be replaced. the grill and lights etc can all be replaced/ reinstalled.

    then I can finish it up with a fresh interior. I'm planning on going with the autumn leaf as thats the color it had and I like it for the seats and door panels, carpet I will just do black as its a nice contrast. I will try to save whatever panels are there, but for the few hundred dollars new panels are cheaper than me trying to rebuild mine. by the time I get the backing, the vinyl, the foam and learn how to do interior, its just not worth it in the end as I wont really save much,

    I will keep documenting as I go along in this thread. I will work on taking pictures as I go and post as much as I can. This is something I hope to have driving within 2 months. optimistic yes. Realistic, Cannot say. but Thats my hope to have it driving. not finished, just driving by then.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Appears you've got a good plan in place. Will be interested to keep up with the project.

    BTW: WD stands for "Water Displacement". I'd recommend the CRC2-26 as the only thing to use on electrical parts and components. WD is more for household uses like squeaky door hinges, not as much for automotive applications. JMHO.
    '64 MGB, '67 Lotus Elan S-3 DHC,'69 Lotus Elan +2
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    I don't know Doc,
    Santa.jpg

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    The WD40 I have ordered is not the standard stuff. its specifically contact cleaner from wd-40

    3314ea5c-096a-489b-9b4f-d6c384af81f6.__CR0,0,785,1046_PT0_SX300_V1___.jpeg

    I got the parts I ordered but wont have the contact cleaner by crc or the wd-40 contact cleaner for a couple more days.

    But It will come along. Ive been spending my time busy with work. lots of clients need me. so already booked for work for the next couple of weeks which is insane. good to be busy, so I am not complaining.

    I spent today having to wait for rain to stop because I needed to finish putting my other car back together as I need to start driving it and my current car will go to my mom so I need to take some parts off it to get painted.

    Going to be doing a bunch of car juggling in the next couple of weeks, but The MG will be running soon i am sure of that. If people can literally make a car thats been sitting in a field run after 30 odd years sitting half buried, I am sure I make this little beauty run.

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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    January 21,2020

    I finally had some time to get to my little blue "B" and do some work at getting the spark back.

    First things first, I replaced the wire in the distributor that connects from the points to the condenser wire and is going from the main harness in to the side of the distributor. the one on the distributor was badly aged and perished.

    Then I got out my feeler gauge that I bought and I checked the points gap. not sure where to set it from, but I did it from the rotor shaft to the little lip on the points and figured that was the way to do it. I also verified the points were not shorted with a continuity meter and all was well.

    Next I tested the coil in the car and still did not seem to have spark it was a Lucas Super coil. I had Voltage on the "+" and continuity to the points on the "-" so figured it was worth a shot to just swap the coil with the other coil I had that came with the car. I was not sure but that's what it seemed to be as that coil in the car did Ohm ok, but I just wasn't convinced it was good.

    So Out came the Lucas Super Coil and I grabbed what appeared to be the original coil that came with the car back in 1972 an old Lucas Coil. Connected it up, Turned the key, and Ladies and Gents, We have a spark! We have signs of Life. See the attached pictures. I may get a new coil in the future. I also picked up a points replacement Accuspark stealth kit. I figure I may use and and if I do I will still carry extra points with me. Either way figured why not have it as an option. It was cheap and I have 3 or 4 extra sets of points and condensers anyway.

    What this tells me is 2 things. 1. The Lucas Super Coil may have been bad. and 2. the wire in the distributor was definitely bad as it crumbled in my hands when I went to swap it out. I may swap the coils around next time I am there and see if it still has spark.

    Now that i had a spark. I decided to clean the bypassed wiring. I first fixed the white/red wire from the ignition to the starter relay and reconnected the wire from the starter relay to the starter. I tested it with an aftermarket bosch relay and it worked and turned the starter, so I then tried the original starter relay and it too also turned the starter so it must be good. So that issue is resolved.

    I then went ahead and redid the alternator wiring with the plug kit i got to allow it to have a proper plug that plugs into the alternator. it only needed 2 wires and so now that is done. so I wrapped some cloth harness tape on the original harness and it looks good.

    I had taken out the distributor without even checking for TDC, so i got piston 1 to the top of its stroke which I hope is TDC. Then i adjusted the distributor rotor to ensure it was pointing at 1. Checked for normal firing order and wires at the correct plugs. it was not in the correct order when I had it previously so I hope all is well there.

    Even though the weber carb is not connected to any linkage, fuel pump or vacuum, I
    poured a little fuel in the carb. Turned the key and after a few cranks, some popping coming from the exhaust. It's like it kind of wants to go. Popping is almost starting in my opinion, so I added more fuel and the best I got was still some popping out of the exhaust. I'll take it. That means My little blue "B" is closer to breathing life again. Its been sitting for 20 years so I didn't expect it to fire off first try, especially with unknown condition of the carb.

    I don't even know if the engine has good compression but it spins freely and I will check for compression next time I am able to look at the car.

    Either way I plan to remove that weber anyway and put the SU AUD493 carbs back on. But figure I may as well see if it will somehow run with the weber and for now alas, it does not. At least the popping is a good sign. That means she will go.

    Very happy to have spark on the little blue car. Now i can focus on the carbs. I want to get it running. Then i can start to deal with the rest.

    While I was at it, I also lubricated the hood release cable and catch with some penetrating oil and worked it and now I can pop the hood without a pair of pliers. took a bit but its usable now and thats good enough. I still need to adjust the hood a bit back as well.

    Happy day. Proud of myself for getting the spark back! One step out of many but one step closer.

    mgb spark 1.jpgmgb spark 2.jpg

  17. #17
    Great Pumpkin DrEntropy's Avatar
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    You may have the timing 180 out. And I misinformed in my post above. I.E: the points trigger the coil to dump as they ~just~ open.

    As a quick-and-dirty way to change the plug wires on the cap; swap 1 &4, and 3 & 2. Spin it again with some fuel down the carb and see.

    You can "static time" the distributor with a test light, the procedure is described here on the Forum a few places. If you don't find it with a search, let us know and will post it again, here.
    '64 MGB, '67 Lotus Elan S-3 DHC,'69 Lotus Elan +2
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Quote Originally Posted by DrEntropy View Post
    You may have the timing 180 out. And I misinformed in my post above. I.E: the points trigger the coil to dump as they ~just~ open.

    As a quick-and-dirty way to change the plug wires on the cap; swap 1 &4, and 3 & 2. Spin it again with some fuel down the carb and see.

    You can "static time" the distributor with a test light, the procedure is described here on the Forum a few places. If you don't find it with a search, let us know and will post it again, here.
    When I did the engine spin to get the #1 piston to the top. I checked and the rotor was pointing at #4. so I rotated again and then inserted the distributor which showed the rotor was pointing at #1. My thought was that you can do it 180 if you have it pointing at #4 then change the firing order as you described. if you have it pointing at #1 on the compression stroke then it would be pointing at #1 so the firing order would be how I have it. but def something for me to look at.

    I also realize I gapped the points wrong. I put the feeler gauge between the distro shaft and the ear on the points. not the gap between the points while the ear had them open. so I think that I also need to readjust that.

    But at least there is spark and signs of wanting to run. It will get there.

    Thank you for the comments and help. I haven't cleaned up any connections yet, but I will all in due time.

  19. #19
    Luke Skywalker
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Pull the plugs and place your thumb over no1 cylinder and turn the motor over...you will know that you are on the compression stroke...unless you want to remove the rocker cover.
    Cheers,
    D.
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  20. #20
    Great Pumpkin DrEntropy's Avatar
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    Re: 1972 MGB Project Blue First attempt and fixing no spark and other checks

    Quote Originally Posted by Grantura_MKI View Post
    Pull the plugs and place your thumb over no1 cylinder and turn the motor over...you will know that you are on the compression stroke...unless you want to remove the rocker cover.
    D means turn the engine by hand...
    '64 MGB, '67 Lotus Elan S-3 DHC,'69 Lotus Elan +2
    '78 Alfa Romeo Spider-undergoing surgery: O=\*/=O
    '84 300D Turbo-"Diesela"-Now my Daily: Oo|≣|oO
    '02 Toyota Camry- SWMBO's 'new-to-her' Daily. <sigh>
    Chaos & Mayhem PTY, LTD..C.I.O. & Floor Sweepervisor

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